Refactor backend and add registry build workflow

currency_service.py

@@ -0,0 +1,107 @@
+"""Exchange-rate retrieval and Stripe currency conversion."""
+
+
+from datetime import datetime
+import requests
+from runtime_config import (
+    CACHE_DURATION,
+    EXCHANGE_RATE_CACHE,
+    EXCHANGE_RATE_LOCK,
+    logger,
+)
+
+__all__ = ['calculate_stripe_amount', 'fetch_exchange_rates', 'get_cached_exchange_rates']
+
+
+
+def calculate_stripe_amount(credits: int, currency: str) -> int:
+    """
+    Calculate amount in smallest currency unit (cents, pence, etc.)
+    Base rate: 100 credits = 1.00 USD
+    """
+    # Get USD price
+    usd_price = credits / 100  # $1 per 100 credits
+
+    # Get exchange rate
+    rates = get_cached_exchange_rates()
+    rate = rates.get(currency, 1.0)
+
+    # Convert to target currency
+    currency_price = usd_price * rate
+
+    # Convert to smallest unit (cents)
+    # Most currencies use 2 decimal places, but some don't
+    if currency in ['JPY', 'KRW']:  # Zero decimal currencies
+        return int(currency_price)
+    else:
+        return int(currency_price * 100)
+
+def fetch_exchange_rates():
+    """
+    Fetch exchange rates from the free currency API
+    Uses EUR as base currency
+    """
+    try:
+        # Using the fawazahmed0 currency API - EUR as base
+        url = 'https://cdn.jsdelivr.net/npm/@fawazahmed0/currency-api@latest/v1/currencies/eur.json'
+
+        logger.info("Fetching exchange rates from API...")
+        response = requests.get(url, timeout=10)
+        response.raise_for_status()
+
+        data = response.json()
+
+        if 'eur' in data:
+            rates_data = data['eur']
+
+            # Extract rates for currencies we support - all relative to EUR
+            new_rates = {
+                'EUR': 1.00,  # Base currency
+                'USD': rates_data.get('usd', 1.5),  # EUR->USD rate
+                'GBP': rates_data.get('gbp', 0.85),  # EUR->GBP rate
+                'PLN': rates_data.get('pln', 4.32),  # EUR->PLN rate
+                'PHP': rates_data.get('php', 60.50),  # EUR->PHP rate
+                'CZK': rates_data.get('czk', 24.65)   # EUR->CZK rate
+            }
+
+            with EXCHANGE_RATE_LOCK:
+                EXCHANGE_RATE_CACHE['rates'] = new_rates
+                EXCHANGE_RATE_CACHE['last_updated'] = datetime.now().isoformat()
+
+            logger.info(f"✅ Exchange rates updated successfully: {new_rates}")
+            return True
+        else:
+            logger.error("Invalid response format from currency API")
+            return False
+
+    except requests.exceptions.Timeout:
+        logger.error("❌ Timeout fetching exchange rates")
+        return False
+    except requests.exceptions.RequestException as e:
+        logger.error(f"❌ Error fetching exchange rates: {e}")
+        return False
+    except Exception as e:
+        logger.error(f"❌ Unexpected error fetching exchange rates: {e}")
+        return False
+
+def get_cached_exchange_rates():
+    """Get cached exchange rates, fetch new ones if cache is stale"""
+    with EXCHANGE_RATE_LOCK:
+        last_updated = EXCHANGE_RATE_CACHE.get('last_updated')
+
+        # If never updated or cache is stale, fetch new rates
+        if last_updated is None:
+            logger.info("Exchange rates cache is empty, fetching...")
+            # Release lock before fetching to avoid deadlock
+        elif (datetime.now() - datetime.fromisoformat(last_updated)).total_seconds() > CACHE_DURATION:
+            logger.info("Exchange rates cache is stale, fetching...")
+        else:
+            # Cache is fresh, return it
+            return EXCHANGE_RATE_CACHE['rates']
+
+    # Fetch new rates (outside lock to avoid blocking)
+    fetch_exchange_rates()
+
+    # Return rates (either newly fetched or fallback)
+    with EXCHANGE_RATE_LOCK:
+        return EXCHANGE_RATE_CACHE['rates']